What Is Machinability Index? Criteria Considered In Evaluating Machinability?

What is machinability index of metal?

Machinability index is used to compare the machinability of different materials in the various cutting process. It is an attempt to quantify the relative machinability of different material. The rated machinability may vary for different cutting operation such as turning, milling, forming etc. In order to find the machinability index, factors like tool material, tool geometry, tool life and other cutting conditions are fixed except the speed. Then find the speed at which tool cut the material for a pre-determined tool life. Then it is compared with a standard material. Here machinability of standard steel is arbitrarily fixed as 100%. The slower speed indicates, low metal removal rate and hence poor machinability.